The present invention relates to a device for locating a rupture in a transparent panel with several panes such as the windshield of the cockpit or windows of airplanes as well as the panel provided with this device.
In the field of transport, there is known the problem of impacts of various origins which can lead to deterioration of the exposed portions of the vehicle such as the windshield or the windows.
Thus, different airborne vehicles as well as terrestrial or marine, are provided with openings provided with protective panels which have as their principal characteristic being transparent.
For reasons of mechanical strength or safety, these panels are constituted by several panes of transparent material:
of mineral origin such as glass, quartz, silica or combinations of these, or
of organic origin such as acrylic, polycarbonate or certain resins or combinations of these.
The association of these materials and their choice are generally dictated by parameters of the conditions of use because the panels thus provided must have structural characteristics suitable for the mechanical resistance necessary to resist:
impacts of different nature, birds, hail, stones, under conditions of use,
variations of pressure, temperature, or
specific phenomena such as abrasion.
The different panes generally have particular functions, separate from each other. There are provided inter-pane layers of adhesives between the different panes so as to connect them to each other to obtain a monolithic panel on the one hand and to obtain effects or to carry out particular actions on the other hand.
Such effects or actions consists in arranging antistatic and/or anti-reflective films, radiation filtration films, films to increase the mechanical resistance or again conductive films to ensure heating in the case of a defrosting function.
It is thus that in the field of aircraft for civil transport, or in the case of high-speed trains, the panels used, particularly the front glass forming the windshield of a cockpit, is made in a known and present fashion by a superposition of three panes of transparent material.
The external pane in contact with the atmosphere has characteristics of resistance to abrasion particularly to resist the blades of a windshield wiper or micro-impacts. This pane does not give mechanical resistance to the panel and is generally of low thickness.
The intermediate pane is a first pane that ensures mechanical resistance properly so-called by taking up all or a portion of the force generated by the conditions of flight in the case of an airplane for example.
The internal pane is a second pane which also ensures mechanical resistance properly so-called by absorbing all or a portion of the forces generated by the conditions of flight in the case of an airplane for example.
In the course of use, such panels can undergo degradation from impacts which give rise to forces greater than the mechanical resistance of the panes, or through accommodation of the effects of mechanical shock and/or thermal shock and/or electric shock. To this is added the weakening resulting from aging of the materials.
To give an idea of the order of magnitude, 5 to 10% of airplanes that fly are affected each year by the degradation of at least one pane of a panel.
In the case of airplanes, this is all the more critical than for other means of transportation because in the case of breakage of a pane, it is necessary that the pilot uses a procedure particular to this type of incident.
Essentially, this procedure consists in decreasing the altitude so that possible depressurization of the apparatus in flight will not be too abrupt.
This has the following immediate consequences:
an increase in fuel consumption because the motors are designed and adjusted to have the best output for a given cruising altitude,
departure from the route to reach the nearest airport,
immediate repair and/or the provision of a replacement airplane when possible,
taking care of the passengers during repair.
This is particularly costly and time-consuming and the consequences to the company image and on profit are considerable.
However, numerous uses of such an emergency procedure could be avoided if the pilot could have an indication of the type of break in the panel. More precisely, it is fundamental that the pilot be able to know which is the panel, the outside, the middle or the interior, which has the break line.
Thus, if only the outside panel is affected, emergency measures are not necessary and the replacement of the panel can be carried out preferably in the course of regular maintenance or at least in a suitable place and with means permitting carrying out this replacement under optimum conditions.
If the intermediate or internal pane has break lines, alone or in addition to the external pane, the emergency procedure should be employed but this time with justification.
The same is true if the three panes are affected, the emergency panel could be all the more taken because the resistance becomes very precarious.
However, in nearly 95% of the cases, only the external panel is affected by the break, which is particularly prejudicial for operators but also for users for whom useless disagreements may arise.
The device according to the present invention has for its object to permit the pilot of the vehicle comprising a transparent panel constituted by at least two panes, more particularly the windshield of an aircraft cockpit, to determine visually whether upon the appearance of a break line in the panel, the latter affects one or several panels and which one or ones.
This device is integrated into the panel and its emplacement is carried out upon production of the panel. Because of this, it is possible to provide new vehicles but also different existing vehicles, with such panels. The production is almost not at all disrupted by the emplacement of this device and the costs are very small compared to what they otherwise would be.
To this end, the device for locating ruptures comprised by at least one break line, in a transparent panel comprising at least two panes, particularly the windshield of an aircraft cockpit, is characterized in that it comprises an opaque or semi-opaque obstacle disposed between two adjacent panes.
This obstacle is a strip disposed as a border of the usable region of the panel.
According to a first embodiment, there is provided an obstacle interposed between two panes.
According to another arrangement, there are provided two multi-pane regions and one obstacle interposed between these two regions.
According to still another arrangement, there are provided n panes and nxe2x88x921 interposed obstacles, interposed one by one between two consecutive panes of which at least one is different.
More particularly, the obstacle is serigraphed onto one of the two facing surfaces of two adjacent panes.
So as to permit better reading, in the case of several obstacles, each obstacle is different from the preceding in shape and/or in dimensions and/or in color.
The invention also comprises the multi-pane transparent panel thus obtained, particularly for the production of an aircraft cockpit windshield.